1. Field of the Invention
The present invention relates to a printer and a control circuit.
2. Description of the Related Art
A POS system capable of managing point of sale (POS) is known as a device that inputs sales, performs deposit and withdrawal of money, and issues a receipt in a store. The POS system includes a POS terminal, a printer, and a peripheral device such as a cash drawer.
Conventionally, a printer connected to a cash drawer has been known. In a typical POS system, a power for the printer is also supplied as a power for the cash drawer. However, a drive voltage of the printer is not necessarily equal to a drive voltage of the cash drawer. In this case, it is necessary to generate the power for the cash drawer inside the printer.
However, a drive time of the cash drawer is extremely short in a time during which the POS system operates. Thus, continuously generating the power for the cash drawer inside the printer considerably reduces the power efficiency.
Thus, the printer may have a configuration that includes a power generation circuit which supplies power to the cash drawer in response to input of a power generation signal, a drive circuit which drives the cash drawer in response to input of a drive signal, and a printer controller which outputs the power generation signal and the drive signal. In order to improve the power efficiency of the printer, such a configuration may employ a method that generates the power for the cash drawer only when the cash drawer is driven. However, in a conventional printer, when the cash drawer is driven simultaneously with the power generation, since the power generation circuit has not yet come up, a preset drive period of the cash drawer may be finished without obtaining a sufficient electric power as an output, which may cause a problem in which the cash drawer cannot be driven.
When the cash drawer that has been used is replaced with a cash drawer of another model, a drive voltage supplied to the cash drawer may differ from the drive voltage before the replacement. In order to cope with this situation, the printer controller may output a voltage designation signal to the power generation circuit to generate a required drive voltage. However, the rise time of the power generation circuit differs between the cash drawers due to the difference in drive voltage, which may cause a problem as described above in which the cash drawer cannot be driven due to the finish of the preset drive period of the cash drawer.
Further, there has been conventionally known a method in which a constant current circuit is provided in a drive circuit inside the printer to drive cash drawers having different drive voltages. However, in such a method, a current is restricted. Thus, an electric power required for the cash drawer cannot be obtained, and the cash drawer cannot be driven with the required drive voltage.
In view of the above, a printer and a control circuit having a high power efficiency have been desired in the art.